I think there are men who could fend her off with a forceful attitude. But I don't see your husband as being able to do it. Maybe he partially wants her, or maybe he just doesn't want to actively hurt another person, or maybe he is just a push-over. I don't know. But he is backed into a corner and he has nowhere to go.
Perhaps if he threatened her with a sexual harassment suit she would stop. But it should not be hard to change a teacher's classroom. Surely this is not the only class at this grade level in the school.
